Antibiosis and parasitism play an important role in bio control of plant diseases. A large number of plant diseases are successfully controlled through bacterial and fungal antagonism. To solve, a fungal antagonist Trichoderma sp., was isolated (antagonist) from the soil sample to be used as a biocontrol agent. The study was to isolate tea plant pathogen; Phomopsis theae from infected tea stem while causes drastic effect in the social, economic aspects of the tea planters. Interaction of Pathogen with Antagonist by various culture methods to prove the biocontrol efficiency was studied by Dual culture method, antibiosis, extraction and bioassay method. The interaction of Antagonists Fungi with the pathogen on the tea plant was studied to know the success of field trials. In the present study, attempts were made to control Phomopsis canker with bio control agents Trichoderma sp under in vitro conditions.
